Trust has been shown to be a key factor for technology adoption by users, that is, users prefer to use applications they trust. While existing literature on trust originating in computer science mostly revolves around aspects of information security, authentication, etc., research on trust in automation-originating from behavioral sciences-almost exclusively focuses on the sociotechnical context in which applications are embedded. The behavioral theory of trust in automation aims at explaining the formation of trust, helping to identify countermeasures for users' uncertainties that lead to lessened trust in an application. We hence propose an approach to augment the system development process of ubiquitous systems with insights into behavioral trust theory. Our approach enables developers to derive design elements that help foster trust in their application by performing four key activities: identifying users' uncertainties, linking them to trust antecedents from theory, deducting functional requirements and finally designing trust-supporting design elements (TSDEs). Evaluating user feedback on two recommender system prototypes, gathered in a study with over 160 participants, we show that by following our process, we were able to derive four TSDEs that helped to significantly increase the users' trust in the system.